1. Field of the Invention
The present invention relates to a brake control system that electrically controls a brake hydraulic pressure for generating a braking force, that is generated by a master-cylinder.
2. Background Art
JP Published Patent Application No. 2007-296963 discloses technology for a brake apparatus that includes a tandem master-cylinder that is operated by a brake operation of a driver, an electrically driven brake booster, and an ABS apparatus. A pressure sensor is provided in each main pipe that extends from primary and secondary chambers of the master-cylinder to the ABS apparatus. The pressures of the primary and secondary chambers of the master-cylinder are detected by the two pressure sensors, and rotation of an electric motor of the electrically driven brake booster is manipulated based on the detection result. As a result, a booster piston advances and retracts with respect to an input piston such that the hydraulic pressure is controlled to a constant pressure.
JP Published Patent Application No. 2008-30599 discloses technology for an electrically driven brake booster including a master-cylinder, an electrically driven actuator, and control means that controls the electrically driven actuator in accordance with movement of a shaft member that advances and retreats in accordance with operation of a brake pedal. A simulator is also provided that generates a reactive force that opposes a depressing force on the brake pedal. According to this technology, when the brake pedal is operated, control is performed such that a booster piston moves to a greater degree than a push rod so that a clearance is formed between the push rod and the piston. At a time of regenerative cooperation that causes the booster piston to retract, a force in a return direction that is transmitted to the push rod from the piston is released by means of the clearance. Thus, a feeling of incongruity is not imparted to the driver.
JP Published Patent Application No. 2009-40290 discloses a brake control apparatus that includes a master-cylinder that is operated by a brake operation of a driver, a brake booster mechanism for applying pressure in wheel-cylinders by operating the master-cylinder separately from the braking operation of the driver, a first control unit that controls an operation of the brake booster mechanism, a hydraulic pressure control part provided separately from the brake booster mechanism and having a hydraulic pressure source capable of applying the pressure in the wheel-cylinders, and a second control unit that controls the operation of the hydraulic pressure control part. The first control unit detects a failure state of the first control unit itself or the brake booster mechanism, and the first or second control unit executes a backup mode that limits the operation of the brake booster mechanism or the hydraulic pressure control part according to the detected failure state.